What's the most frustrating user-interface element?
Many people would say the progress bar. It stutters, it lies, and the one I have here has been telling me 100% for five minutes now but not going away.
Here's a link to an interesting little study about psychological optimizations programmers can make so their progress bars feel faster, even if the process takes the same time to complete. Reduce inexplicable pauses, and make it get quicker toward the end. I would add to that: don't patronize me with transparent falsehoods like "less than a minute remaining" for hours on end.
(Image borrowed from TheDailyWTF, where I had lots of choices)
